Preparation and evaluation of a self-emulsifying drug delivery system of etoposide–phospholipid complex

The aim of this study was to develop a new phospholipid complex self-emulsifying drug delivery system (PC-SEDDS) to enhance bioavailability of oral etoposide, a drug with poor water solubility.Etoposide-phospholipid complex (EPC) was prepared by reacting etoposide and phospholipid in tetrahydrofuran and confirmed as a phospholipid compound by differential scanning calorimetry (DSC). Solubility of EPC and etoposide was determined in various vehicles. Pseudoternary phase diagrams were constructed to identify the efficient self-emulsification region of EPC-SEDDS, and the effects of oil concentration, drug loading, and aqueous media on droplet size were investigated.The optimal formulation of EPC-SEDDS was EPC:octyl and decyl monoglyceride (ODO):Cremopher EL:PEG-400 (1:20:48:32) (w/w/w/w). Compared with etoposide-phospholipid complex suspension (EPCS) and etoposide suspension (ES), cumulative release of etoposide from EPC-SEDDS increased by 1.31 and 2.65 fold at 24 hours, respectively. Compared with ES, relative bioavailability of EPC-SEDDS, E-SEDDS, and EPCS after oral administration in rats was enhanced by 60.21-, 44.9-, and 8.44- fold, respectively.The synergistic effect between PC and SEDDS contributed to the enhanced bioavailability of etoposide. It was concluded that PC-SEDDS proved to be a potential system for delivering orally administered hydrophobic compounds including etoposide.